This commit updates the srf06-cc26xx platform by adding support for the CC1310EM.
We generalise the way this platform selects CPU/board so that we can easily add more combinations in the future. These changes have implication on how to build for different devices, so make sure to have a look at the updated README
Instead of using a separate data structure to request that a PD remain powered during deep sleep,
we do the same within the main LPM data structure through an additional field.
This allows us to maintain only one linked list of LPM modules and overall improves code clarity
